Declaration

Overview

Figure 1

A cone and its properties

A cone defines the surface of a solid whose base is a circle and whose side surface tapers to a point centered above its base. A frustum also has a circular base and tapered sides but has a circular top, similar to a cone cut off below its apex.

Define the size of the cone’s base in the x- and z-axis dimensions of its local coordinate space with its bottomRadius property, and its extent in the y-axis dimension with its height property. Create a cone that tapers to a point by setting its topRadius property to zero, or a frustum that tapers (or expands) to a circular top by setting the topRadius property to a different value.

To position and orient a cone in a scene, attach it to the geometry property of an SCNNode object.

Control the level of detail with the radialSegmentCount and heightSegmentCount properties. A higher radial segment count creates a smoother curve for the cone’s circular sides. A higher segment count in either direction produces more vertices, which can improve rendering quality for certain lighting models or custom shader effects, but at a cost to rendering performance.

A cone geometry may contain two or three SCNGeometryElement objects, corresponding to its outer surface, its base and its top (or base only or top only, if the topRadius or bottomRadius property is zero). SceneKit can render each element using a different material. For details, see the materials property in SCNGeometry.